firewire: switch ioctl_queue_iso to use of copy_from_user()

no point trying to do access_ok() for all those __copy_from_user()
at once.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/firewire/core-cdev.c

@@ -1081,8 +1081,6 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
 		return -EINVAL;
 
 	p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);
-	if (!access_ok(p, a->size))
-		return -EFAULT;
 
 	end = (void __user *)p + a->size;
 	count = 0;
@@ -1120,7 +1118,7 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
 			&p->header[transmit_header_bytes / 4];
 		if (next > end)
 			return -EINVAL;
-		if (__copy_from_user
+		if (copy_from_user
 		    (u.packet.header, p->header, transmit_header_bytes))
 			return -EFAULT;
 		if (u.packet.skip && ctx->type == FW_ISO_CONTEXT_TRANSMIT &&